Phytochemical studies on the aerial parts of Prangos uloptera, an endemic Iranian species of the genus Prangos, yielded five coumarins, xanthotoxin (1), prangenin (2), scopoletin (3), deltoin (4) and prangolarin (5). The structures of these coumarins were elucidated by spectroscopic means, and the antioxidant potential of 1-5 was evaluated by the DPPH assay. The chemotaxonomic significance of 1-5 is also discussed.